CONTROL METHOD FOR TRANSIENT VARYING LOAD COAL SUPPLY QUANTITY CONSIDERING EXERGY STORAGE MODIFICATION OF COAL-FIRED BOILER

摘要

The present invention discloses a control method for transient varying load coal supply quantity considering exergy storage modification of a coal-fired boiler. The method comprises: measuring and recording in real time the working medium of a coal-fired boiler system and the temperature and pressure of the metal heating surface for conversion into exergy storage capacities at different operating load points; comparing, during the transient operating process, the real time exergy storage capacity of the boiler system with the exergy storage capacity of the corresponding steady-state load point so as to obtain a real time exergy storage variable; and then superposing the feedforward control signal for inputting coal supply quantity to the existing boiler coal supply quantity instruction so as to finally produce a boiler coal supply quantity signal based on the boiler exergy storage modification. The method according to the present invention performs feedforward modification to the coal supply quantity at the boiler inlet using the boiler exergy storage difference during transient process to realize dynamic accurate control of the coal quantity at the inlet, thereby guaranteeing the stability of the parameters of each thermal devices, weakening the function of thermal inertia and time delay, and greatly increasing the operating flexibility of the coal-fired generator unit during transient process as well as balancing economic efficiency and safety.